Harry watched as she waved her wand near the washing line, and the damp clothes rose into the air to hang themselves up, and suddenly he felt a great wave of remorse for the inconvenience and the pain he was giving her.

Ron responded by maintaining an unnaturally somber demeanor in her presence as an outward sign of continuing remorse.

He turned away; there was no sadness in him, no remorse.

Is this remorse, Severus?

They say he showed remorse in later years, alone in his cell at Nurmengard.